Sunday, August 25, 2013

Copper for a coach roof

Individual copper sheets were attached
with a folded seam and soldered.
Most early 20th Century railroad coaches had canvas roofs.  Some railroads specified that the entire roof be clad with canvas while others preferred copper cladding on the car ends. Copper was not an afterthought but an option specified when the cars were built.  Oxidation and the limitation of black and white photography often make it difficult to identify this in the 1912-era photos, but the Museum is confident that coach 218 was built with copper hoods. 

Completed lower hood.  One improve-
ment over 1912 materials is the use of
marine calking to seal edges.
Certainly one of coach 218's distinguishing features is this copper cladding on the roof ends, but unfortunately the original surviving copper was brittle and riddled with perforations.  So restoring these to their "as built" appearance and condition has been one of the project priorities. These "hoods" feature compound curves and are areas where it is more difficult to keep out rain water on this design of railroad car.  The copper cladding improves durability and reduces long term maintenance. (Some years ago, Spike had an opportunity to work on two Canadian Pacific Railway passenger cars that featured full canvas roofs and can attest to the fact that the canvas fails first on the compound curve at the ends of the cars.)

Bob M. attached the last of the clere-
story cladding to allow the final piece
of copper to be attached.
The design of the hoods is simple but the tin smith skills to install it are no longer common.  Fortunately, Gary J. is a highly accomplished marine carpenter and this work was an easy adaptation for him.  To begin, copper sheets were cut into small rectangular sections that would conform to the roof curve.  The edges were bent up or over to allow a folded seam with the adjacent roof panels.  All the seams were tapped flat and then soldered to provide a watertight seal.  The final product mimics the original roof but the appearance of the soldered seam is slightly different, probably because of the difference in performance between an internally and externally heated soldering iron.

Completed copper hoods debuted dur-
ing Railroad Days 2013.
Work continues on coach 218 but completion of the copper hoods allowed its use during Railroad Days 2013 where it carried an estimated 120 additional passengers.  Work is being funded with the generous support of 4Culture, the Nysether Family Foundation, proceeds from GiveBIG 2013, the Snoqualmie Tribe, and individual contributions from people just like you!

Thursday, August 8, 2013

Smoke or heat?

A critical responsibility of every museum is the general protection of the Collection.  Broadly defined, that could mean protecting it from everything, which is unrealistic.   However, prudent steps can be taken to protect the collection from things that could reasonably occur.  Examples may include exposure to bright sunlight, rapid changes in heat or humidity, small to moderate earthquakes, and fire. 

An articulated lift allows a fire alarm
technician to exchange fire detection
sensors inside the Train Shed, high above
chapel car Messenger of Peace.
Inside the Northwest Railway Museum's new Train Shed exhibit building, some of the most important and representative objects in the Collection are protected with UV-filtering windows, R-30  insulation, a structure designed to the most modern seismic code, and a fire detection and suppression system.  Yet no system is perfect and unfortunately the Museum has had a variety of issues with the fire detection system. 

Local codes required smoke detectors in the original construction because, as Spike has been advised, they often detect a fire sooner than a heat sensor.  However, in a building with fans running all the time and nearly 750,000 cubic feet of air, there have been problems with these sensors.  Since completion in 2010, the Train Shed has experienced as many as 50 false alarms.  Fortunately, the Snoqualmie Fire Department has been very understanding and supportive, and several fire fighters now know almost as much about the Collection as some of the regular docents.  However a problem like this cannot be allowed to continue. Aside from the story about The Boy Who Cried Wolf, what if the fire department is responding to a false alarm when your house is on fire?

The Museum and its contractor partners have worked hard to determine the cause of the false alarms from the smoke detectors.  The Train Shed is not particularly dusty - in fact a lot cleaner than the Conservation and Restoration Center, which also has a number of smoke detectors.  There are no sudden changes in temperature that could cause condensation to form inside the detectors. The model of sensor does not have a history of issues.  There has even been consideration as to whether an infestation of insects or spiders is causing the problem. However, without being able to pinpoint an exact cause, it has been determined that smoke detectors are not reliable inside the Train Shed, and the local municipality approved a change. 

Early in August 2013, E Squared Systems was on site to replace the smoke detectors with heat sensors. This is quite a feat in a structure filled with artifacts, with ceilings as high as 35 feet, and not a lot of floor space to operate a 14,000-pound lift.  Now the Museum looks forward to improved reliability, and the Snoqualmie Fire Department looks forward to fewer late night museum visits.